Network Working Group S. Mackie
Internet-Draft Juniper Networks
Intended status: Standards Track L. Fang
Expires: June 18, 2017 eBay
N. Sheth
Juniper Networks
M. Napierala
AT&T Labs
N. Bitar
Nokia
December 15, 2016
BGP-Signaled End-System IP/VPNs
draft-ietf-l3vpn-end-system-06
Abstract
This document describes a solution in which the control plane
protocol specified in BGP/MPLS IP VPNs is used and extended via the
XMPP protocol to provide a Virtual Network service to end-systems
(hosts). These end-systems may be used to provide network services
or may host end-user applications.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on June 18, 2017.
Copyright Notice
Copyright (c) 2016 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3
2. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Applicability of BGP IP VPNs . . . . . . . . . . . . . . . . 4
4. Virtual Network End-Points . . . . . . . . . . . . . . . . . 7
5. VPN Forwarder . . . . . . . . . . . . . . . . . . . . . . . . 9
6. XMPP signaling protocol . . . . . . . . . . . . . . . . . . . 11
7. End-System Route Server behavior . . . . . . . . . . . . . . 21
8. Operational Model . . . . . . . . . . . . . . . . . . . . . . 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
10. Security Considerations . . . . . . . . . . . . . . . . . . . 25
11. XML schema . . . . . . . . . . . . . . . . . . . . . . . . . 26
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 28
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 28
13.1. Normative References . . . . . . . . . . . . . . . . . . 29
13.2. Informational References . . . . . . . . . . . . . . . . 30
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 31
1. Introduction
This document describes the requirements for a network virtualization
solution that provides an IP service to end-system virtual
interfaces. It then discusses how the control plane for BGP IP VPNs
[RFC4364] can be used and extended via the XMPP protocol to provide a
solution that meets these requirements. Subsequent sections provide
a detailed discussion of the control and forwarding plane components.
In BGP IP VPNs, Customer Edge (CE) interfaces connect to a Provider
Edge (PE) device which provides both the control plane and VPN
encapsulation functions required to implement a Virtual Network
service. This document describes how the control plane and
forwarding functionality of a PE device can be decoupled in order to
enable the forwarding functionality to be implemented in multiple
devices. For instance, the forwarding function can be implemented
directly on the operating system of application servers or network
appliances.
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1.1. Terminology
This document makes use of the following terms:
End-System: A compute node whose primary function is to run
applications. It is assumed that end-systems support multiple
application instances (e.g., virtual machines), each with its
independent network configuration.
End-System Route Server: A software application that implements the
control plane functionality of a BGP IP VPN PE device and an XMPP
server that interacts with VPN Forwarders.
Virtual Interface: An interface in an end-system that is used by a
virtual machine or by applications. It performs the role of a CE
interface in a BGP IP VPN network. This is similar to the concept
of Virtual Access Point (VAP) in RFC 7365 [RFC7365].
VPN Forwarder: The forwarding component of a BGP IP VPN PE device.
This functionality may be co-located with the virtual interface or
implemented by an external device.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
2. Requirements
Network virtualization is used in both service provider as well as
enterprise networks to support multi-tenancy and network-based access
control. It may also be used to facilitate application instance
mobility.
Multi-tenancy allows a physical network to provide services to
multiple "customers" or "tenants", whether these are external
entities in the case of a Service Provider providing managed VPN
services, or internal departments of an enterprise sharing an IT
facility. Multi-tenancy requires isolation of traffic and routing
information between tenants.
Within a tenant, it is often required to create multiple distinct
virtual networks, in order to be able to provide network-based access
control. In this service model, each virtual network behaves as a
"Closed User Group" (CUG) of virtual interfaces that are allowed to
exchange traffic freely, while traffic between virtual networks is
subject to access controls. This scenario can be found in enterprise
campus networks, branch offices and data centers.
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It is often the case when network access control is used, that the
traffic patterns are such that there is significantly more traffic
crossing a CUG boundary than staying within such boundary. As an
example, in campus networks it is common to segregate users into CUGs
based on some classification such as the user's department. Campus
networks often see traffic patterns in which almost all the traffic
flows northbound to the data center or internet boundaries. Similar
traffic patterns can be found in multi-tier applications in IT data
centers.
Virtual interfaces are often configured to expect the concept of IP
subnet to match its closed user group. A network virtualization
solution should be able to provide this concept of IP subnet
regardless of whether the underlying implementation uses a multi-
access network or not.
Virtual interfaces should be able to directly access multiple closed
user groups without needing to traverse a gateway. Network access
policy should allow this access whether the source and destination
CUGs for a particular traffic flow belong to the same tenant or
different tenants. It is often the case that infrastructure services
are provided to multiple tenants. One such example is voice-over-IP
gateway services for branch offices.
Independently, but often associated with the previous two functions,
IP mobility is another network function that can be implemented using
network virtualization. By abstracting the externally visible
network address from the underlying infrastructure address, mobility
can be implemented without having to rely upon home agents or large
L2 broadcast domains.
IP Mobility requires the ability to "move" a virtual interface
without disrupting its TCP (or UDP) transport sessions. This
requires a mechanism that can efficiently communicate the mappings
between logical and physical addressing.
IP Mobility can be a result of devices physically moving (e.g., a
WiFi enabled laptop) or workload being diverted between physical
systems such as network appliances or application servers.
3. Applicability of BGP IP VPNs
BGP IP VPNs [RFC4364] is the industry de-facto standard for providing
"closed user group" functionality in WAN environments. It is used by
service providers in environments where several millions of routes
are present. It supports both isolated VPNs as well as overlapping
VPNs (often referred to as "extranets").
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The BGP IP VPN control plane has been designed to be able to
distribute the mapping between virtual address and location (next-
hop) to the subset of network nodes for which this information is
relevant, whenever that mapping changes. This provides an efficient
mechanism to address IP mobility requirements as compared to methods
that depend on a (cached) mapping request from the end-systems.
In its traditional usage in Service Provider networks, BGP IP VPN
functionality is implemented in a Provider Edge (PE) device that
combines both BGP signaling as well as VRF-based forwarding
functions. In practice, most PE devices in current use are multi-
component systems with the signaling and forwarding functionality
actually implemented in different processors attached to an internal
network.
This document assumes a similar separation of functionality in which
software appliances, the End-System Route Servers, implement the
control plane functionality of a PE device and a VPN Forwarder
implements the forwarding function usually found in a PE device
"line-card". The VPN Forwarder functionality may be co-located with
the end-system (e.g., implemented in the hypervisor switch or host OS
network drivers) or it may be external. For instance, residing in a
data center switch or specialized appliance.
Operationally, BGP IP VPN technology has several important
characteristics:
o It has a high-level of aggregation between customer interfaces and
managed entities (Provider Edge devices).
o It defines VPNs as policies, allowing an interface to directly
exchange traffic with multiple VPNs and allowing for the topology
of the virtual network to be modified by modifying the policy
configuration.
o It scales horizontally in terms of event propagation. By
increasing the number of signaling devices implementing the PE
control plane, it is possible to decrease the load on each
signaling device for events that originate in a specific location
and which must be propagated across the network.
The last point is particularly relevant to the convergence
characteristics required for large scale deployments. BGP's
hierarchical route distribution capabilities allow a deployment to
divide the workload by increasing the number of End-System Route
Servers.
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As an example consider a topology in which 100 End-System Route
Servers are deployed in a network each serving a subset of the VPN
forwarding elements. The Route Servers inter-connect to two top-
level BGP Route Reflectors [RFC4456].
If an event (i.e., a VPN route change) needs to be propagated from a
specific end-system to 10,000 clients randomly distributed across the
network, each of the End-System Route Servers must generate 100
updates to its respective downstream clients.
By modifying this topology such that another 100 End-System Route
Servers are added, each Route Server is now responsible for
generating 50 client updates. This example illustrates the linear
scaling properties of BGP: doubling the number of Route Servers
(i.e., the processing capacity) reduces by half the number of updates
generated by each one (i.e. the load at each processing node is
halved).
The same horizontal scaling techniques can be applied to the Route
Reflector layer in the example above by dividing the VPN Route space
according to some pre-defined criteria (for instance VPN route
target) and using a pair of Route Reflectors per subset.
In the previous example we assumed a dense membership in which all
Route Servers have local clients that are interested in a particular
event. BGP also optimizes the route distribution for sparse events.
The Route Target Constraint [RFC4684] extension, builds an optimal
distribution tree for XMPP stanza and message propagation based on
VPN membership. It ensures that only the PEs with local receivers
for a particular event do receive it also decreasing the total load
on the upstream BGP speaker.
In the WAN environment, BGP IP VPN control plane scaling is not
primarily focused on route convergence times, but on the memory
footprint of embedded devices. While memory footprint does not have
a similar linear scaling behavior as load, memory technology
available to software appliances is often at 10x the scale of what is
commonly found in WAN environments, and so is not so much of a
concern.
The functionality present in the BGP IP VPN control plane addresses
the requirements specified in the previous section. Specifically, it
supports multiple potentially overlapping "groups", regular or "hub
and spoke" topologies and the scaling characteristics necessary.
The BGP IP VPN control plane supports not only the definition of
"closed user-groups" (VPNs in its terminology) but also the
propagation of inter-VPN traffic policies [RFC5575].
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Note that the signaling protocol itself is rather agnostic of the
encapsulation used on the wire as long as this encapsulation has the
ability to carry a label of sufficient length to enumerate all the
VPNs in an administrative domain (e.g. an MPLS label, which has 20
bits).
Several network environments use a network infrastructure that is
only capable of providing an IP unicast service. In order to support
them, implementations of this document should support the MPLS in GRE
[RFC4023] encapsulation. Other encapsulations are possible,
including UDP-based encapsulations RFC 7510 [RFC7510] and VXLAN
[RFC7348].
4. Virtual Network End-Points
This document assumes that end-systems support one or more virtual
network interfaces in addition to a physical interface that is
associated with the underlying network infrastructure. A virtual
network interfaces can be associated with a specific application via
a OS-dependent mechanisms like a Virtual Machine (VM), or they can be
used to provide network connectivity to all user applications in the
same way that a "VPN tunnel" interface is used to provide access
between an end-system (e.g., a laptop) and a remote corporate
network.
Each virtual network interface is assigned an IP addresses from a
subnet associated with a "closed user group" or VPN, while the
physical interface of the machine is addressed in the network
infrastructure topology.
A virtual network interface is connected to a VPN Forwarder. This
VPN Forwarder MAY be co-located in the end-system or external. In
cases where the VPN Forwarder is external to the end-system, they can
either be directly connected or interconnected with a dedicated
802.1Q VLAN on a per virtual interface basis.
Both static and dynamic IP address allocation can be supported. The
latter assumes that the VPN Forwarder implements DHCP relay or DHCP
proxy functionality.
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Traffic that ingresses or egresses through a virtual network
interface is routed at the VPN Forwarder, which acts as the first-hop
router (in the virtual topology). The IP configuration on the client
side of this virtual network interface (e.g., in the guest OS) can
follow one of two models:
o Point-to-point interface model
o Multipoint interface model
In a point-to-point interface model, the VPN client routing table
(e.g., on the guest OS) contains the following routing entries: a
host route to the local IP address, a host route to the first-hop
router via the virtual interface and a default route to the first-hop
router. This is the model typically used in "VPN tunnel"
configurations or other access technologies such as cable deployments
or DSL. When this model is used, the first-hop router IP address is
either an address from the tenant's IP address space or a link-local
address. This address SHOULD be the same on all first-hop routers
across a specific deployment so that it does not change when a
virtual interface moves between end systems.
In a multi-point interface model, the VPN client routing table (e.g.,
on the guest OS) contains the following routing entries: a host route
to the local IP address, a subnet route to the local interface and
optionally a default route to a specific router address within that
subnet. In this model, the VPN client IP stack will issue address
resolution requests for any IP addresses it considers to be directly
attached to the subnet. The VPN Forwarder SHALL answer all address
resolution requests via Proxy ARP [RFC1027].The same technique is
applicable when Neighbor Discovery is used to resolve IPv6 addresses.
Address resolution request SHOULD be answered using a virtual MAC
address which SHOULD be the same across all VPN Forwarders in a
specific deployment. This virtual MAC address SHALL default to the
VRRP [RFC5798] virtual router MAC address for Virtual Router
Identifier (VRID) 1.
When the virtual topology first-hop router resides on the same
physical machine, the host OS is responsible for mapping the virtual
interface with a VPN-specific routing table (without taking L2
addresses into consideration). In this case the MAC addresses known
to the guest OS are not used on the wire.
When the virtual topology first-hop router resides in an external
system (e.g., the first hop-switch) the virtual interface shall be
identified by the physical interface of the end-system and a 802.1Q
VLAN tag. The first-hop switch should use a virtual router MAC
address to answer any address resolution queries.
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Whenever external VPN forwarding is used, and resiliency is desired,
multiple external VPN Forwarder may be employed in a redundant
configuration. It is desirable to use VRRP as a mechanism to control
the flow of traffic between the end-system and the external VPN
Forwarder. VRRP already defines the necessary procedures to elect a
single forwarder for a LAN.
This specification uses the VRRP virtual router MAC address as the
default L2 address for the VPN Forwarder, in order to support a
client virtual interface moving between locations.
While the VRRP Virtual Router MAC will be used to answer any address
resolution request made by the virtual interface client (e.g., the
guest VM) this does not imply that a single default router is elected
per virtual IP subnet. The ingress VPN Forwarder will perform an IP
forwarding decision based on the destination IP address of the
(payload) traffic.
VRRP router election is only relevant in selecting the VPN Forwarder
associated with a specific machine, when external forwarders are in
use.
5. VPN Forwarder
In this solution, the Host OS/Hypervisor in the end-system must
participate in the virtual network service. Given an end-system with
multiple virtual interfaces, these virtual interfaces must be mapped
onto the network by the end system OS such that applications on one
virtual interface cannot send traffic to networks they are not
authorized to communicate with or using source addresses not assigned
to the virtual interface.
When VPN forwarder functionality is implemented by the Host OS/
Hypervisor, intermediate systems in the network do not require any
knowledge of the virtual network topology. This can simplify the
design and operation of the physical network.
When it is not possible or desirable to add the VPN forwarding
functionality to the end-system, it may be implemented by an external
system, typically located as close as possible to the end-system
itself.
Both models, co-located and external VPN Forwarder can co-exist in a
deployment.
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In order to implement the BGP IP VPN Forwarder functionality a device
MUST implement the following functionality:
o Support for multiple "Virtual Routing and Forwarding" (VRF)
tables;
VRF route entries map prefixes in the virtual network topology
to a next-hop containing a infrastructure IP address and a
label allocated by the destination Forwarder. The VRF table
lookup follows the standard IP lookup (best-match) algorithm.
o Associate an end-system virtual interface with a specific VRF
table;
When the Forwarder is co-located with the end-system, this
association is implemented by an internal mechanism. When the
Forwarder is external the association is performed using the
MAC address of the end-system and an IEEE 802.1Q tag that
identifies the virtual interface within the end-system.
o Encapsulate outgoing traffic (end-system to network) according to
the result of the VRF lookup;
o Associate incoming packets (network to end-system) to a virtual
interface for direct forwarding, or to a VRF for lookup, according
to the label contained in the packet;
The VPN Forwarder MAY support the ability to associate multiple
virtual interfaces with the same VRF. When that is the case, locally
originated routes, that is IP routes to the local virtual interfaces
SHALL NOT be used to forward outbound traffic (from the virtual
interfaces to the outside) unless a route advertisement has been
received that matches that specific IP prefix and next-hop
information. This is intended to ensure that the forwarding behavior
is the same whether the VRF is shared or between multiple interfaces
of the same virtual-network or not.
As an example, if a given VRF contains two virtual interfaces,
"veth0" and "veth1", with the addresses 203.0.113.1/32 and
203.0.113.2/32 respectively, the initial forwarding state must be
initialized such that traffic from either of these interfaces does
not match the other's routing table entry. It may, for instance,
match a default route advertised by a remote system. Traffic
received from other VPN Forwarders, however, must be delivered to the
correct local interface. If at a subsequent stage a route is
received from the Route Server such that 203.0.113.2/32 has a next-
hop with the IP address of the local host and the correct label, the
system may subsequently install a local routing table entry that
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delivers traffic directly to the "veth1" interface. This means that
forwarding table entries apply to downstream traffic only, by
default. This capability can be used to implement a hub-and-spoke
topology, if required.
The label which is associated with a virtual interface is of local
significance only and SHOULD be allocated by the VPN Forwarder.
When an external VPN Forwarder is used the end-system MUST associate
each virtual interface with a VLAN [IEEE.802-1Q] that is unique on
the end-system. The switching infrastructure SHOULD be configured
such that multi-destination frames sourced from an end-system are
only delivered to VPN Forwarders used by this end-system and not to
other end-systems.
6. XMPP signaling protocol
End-System Route Servers must be aware of VPN membership on each
Forwarder as well as what IP addresses are currently associated with
each virtual interface.
VPN Forwarders receive VPN route information from which to populate
their forwarding tables. External VPN Forwarders also need to
receive the virtual interface and IP address allocation events for
the end-system for which they are VPN forwarders. In this case, the
end-system assigns an 802.1Q VLAN tag to each virtual interface and
communicates that information to the Forwarder directly, or via the
Route Server.
In order to exchange this information this specification uses the
XMPP [RFC6120] protocol along with the Publish-Subscribe [pubsub]
extension.
VPN forwarders (both co-located and external) establish XMPP sessions
with End-System Route Servers, acting as XMPP clients. When an
external VPN Forwarder is used, end-systems MAY establish XMPP
sessions with VPN Forwarders. In such cases, external VPN Forwarders
act as XMPP servers for end-systems which are associated with them.
A VPN Forwarder MAY connect to multiple End-System Route Servers for
reliability. In this case it SHOULD publish its information to each
of the Route Servers. It MAY choose to subscribe to VPN routing
information from only one of the available Route Servers. In this
case, the Forwarder is responsible for switching subscriptions over
to an alternate Route Server in the case of Route Server failure.
Alternatively, it MAY choose to subscribe to VPN routing information
from more than one End-System Route Server. In this case, the
Forwarder is responsible for selecting which Route Server is
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authoritative for each forwarding entry. The Route Servers SHOULD
produce the same forwarding information for each destination. The
VPN Forwarder is expected to select the entry that it deems as more
recent for positive updates. It SHOULD NOT consider a forwarding
entry to be withdrawn unless it is withdrawn by both Route Servers.
Each End-System Route Server MUST monitor the XMPP connection status
of each VPN Forwarder that is connected to it. The information
advertised by an XMPP client SHOULD be deleted after a configurable
timeout, after XMPP session closes. This timeout SHOULD default to
60 seconds.
An End-System Route Server MAY monitor the status of each VPN
Forwarder that is connected to it, using, for example, the BFD
[RFC5880] protocol and to delete advertised information after a
timeout when a failure is detected. The Route Server MAY choose to
immediately reduce the preference of routing information received
from an XMPP client for which a failure has been detected, either
through an XMPP session close event, or a failure detection mechanism
such as BFD.
+---------+ +--------+
| RS |--------| BGP |
+---------+ +--------+
/ \ /
XMPP \ /
/ \ /
+--------------------+ \ /
| End | VPN | \/
| System | Forwarder | /\
+--------------------+ / \
\ / \
XMPP / \
\ / \
+---------+ +--------+
| RS |--------| BGP |
+---------+ +--------+
VPN Forwarder Connected to Two Routing Systems
Figure 1
The figure above represents a typical configuration in which an end-
system with a co-located VPN Forwarder is directly connected to two
End-System Route Servers, which are in turn connected to multiple BGP
speakers which may be other L3VPN PEs or BGP route reflectors.
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In deployment, the number of End-System Route Servers used will
depend on the desired Route Server to VPN Forwarder ratio which
affects the convergence time of event propagation.
The XMPP JID used by the client SHALL be a RFC 7622 [RFC7622]
compliant address that uniquely identifies it in its administrative
domain. The VPN Forwarder SHOULD use its hostname as JID, when
available, or a unique IP address within the infrastructure network
using its string representation. The same naming convention SHOULD
be used for an End System which has an XMPP session with an external
VPN Forwarder.
The XMPP JID used by an End-System Route Server SHOULD be the
constant string 'route-server@ietf.org'.
Each VPN shall be identified by an ASCII character string that SHOULD
NOT exceed 128 octets and MUST be unique within each administrative
domain. The VPN identifier is an attribute of each virtual
interface. It is assumed that a configuration management system
exists such that it provisions the Route Servers with VPN identifier
values and the VPN Forwarders with the mapping of virtual interface
to VPN identifier. Such a configuration management system is outside
the scope of this document.
Each VPN identifier corresponds to a Pub-Sub node in the Route Server
XMPP servers. This Pub-Sub nodes SHOULD be configured such that Pub-
Sub items are persistent and that event notifications include the
item payload. Implementations MAY choose to perform this operation
explicitly or implicitly by mapping XMPP subscription requests to an
event observer mechanism that tracks the VRF table corresponding to
the VPN in question.
When an external Forwarder is used, its control software MAY operate
as an XMPP server which processes requests from end-systems and SHALL
operate as a client of one or more End-System Route Servers. The
control software relays to the End-System Route Server(s) VPN
membership stanzas it receives from the end-system. VPN routing
information received from the Route Server(s) SHOULD NOT be
propagated to the end-system unless it specifically requests such
information. End systems MAY have sessions directly with the End-
System Route Servers, and in this case no XMPP sessions are required
with VPN Forwarders.
When a virtual interface is created on an end-system, the host End
System XMPP client SHALL generate an XMPP Subscribe stanza to its
server (a Route Server or the external VPN Forwarder).
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Each Subscribe stanza SHALL be addressed to the JID of the Route
Server (e.g. route-server@ietf.org), using the VPN Identifier as the
NodeID.
If subsequent Virtual Interfaces are created with the same VPN
Identifier, and the previous Pub-Sub subscription is still in effect,
then additional XMPP Pub-Sub Subscribe stanzas SHOULD NOT be sent to
the End-System Route Server.
Example subscription request from co-located VPN Forwarder to Route
Server:
<iq type='set'
from='forwarder@domain.org'
to='route-server@ietf.org'
id='sub1'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<subscribe node='vpn-customer-name' jid='fowarder@domain.org'/>
<options>
<instance-id>1</instance-id>
</options>
</pubsub>
</iq>
The above request instructs the End-System Route Server to start
populating the client's VRF table with any routing information that
is available for this VPN. The XMPP node 'vpn-customer-name' is
assumed to be implicitly created by the End-System Route Server.
Creation of a virtual interface may precede any IP address becoming
active on the interface, as is the case with VM instantiation.
The optional "instance-id" element allows the VPN Forwarder to
specify a unique 16 bit index that can be used by the Route Server to
automatically assign a Route Distinguisher (RD) to any route
subsequently advertised by the VPN Forwarder. In a scenario where
the VPN Forwarder is advertising reachability information to multiple
Route Servers it is desirable for reachability information to have an
RD composed of the VPN Forwarder identifier (e.g., IPv4 address) and
the "instance-id".
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Example subscription request from end-system to external VPN
Forwarder:
<iq type='set'
from='end-system@domain.org'
to='forwarder@domain.org'
id='sub1'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<subscribe node='vpn-customer-name' jid='forwarder@domain.org'/>
<options>
<x xmlns='jabber:x:data' type='submit'>
<field var='vpn#vlan_id'><value>100</value></field>
</x>
</options>
</pubsub>
</iq>
When an external VPN Forwarder is used, the end-system SHOULD include
the VLAN identifier it assigned to the virtual interface as a
subscription option. This option is represented in the XMPP Pub-Sub
Subscribe stanza a data form [xep-0004] field with the name
"vpn#vlan_id". The example above uses the 802.1Q tag value of 100.
When a Route Server receives a subscription request for a specific
VPN identifier it SHALL treat this request as an implicit request for
item retrieval for all items in the Pub-Sub node that corresponds to
the VPN.
If at any point all Virtual Interfaces associated with a given VPN
Identifier are removed or deactivated from the End-System, then the
End System XMPP client SHOULD generate an XMPP Pub-Sub Unsubscribe
stanza to its server for the Pub-Sub node associated with the VPN
Identifier.
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Example unsubscribe request from co-located VPN Forwarder to Route
Server:
<iq type='set'
from='forwarder@domain.org'
to='route-server@ietf.org'
id='unsub1'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<unsubscribe
node='vpn-identifier'
jid='forwarder@domain.org'/>
</pubsub>
</iq>
For a collocated VPN forwarder, and for an external VPN forwarder
when there is an XMPP session with the End System, when an IP address
is added to a virtual interface and the interface is activated, the
end-system SHALL generate an XMPP Pub-Sub Publish request. This
request publishes an item containing a single entry element based on
the XML Schema Definition in Section 11. The ItemID of this item
MUST be generated by the VPN Forwarder such that the value is unique
within a Pub-Sub node. The ItemID MAY be formed by combining the VPN
Forwarder's IP address, the instance-id value, and the entry address
element. This format corresponds to the string representation of a
BGP L3VPN NLRI in which the Route Distinguisher is given by the VPN
Forwarder IP address and instance-id, and is easily identifiable by
network operators. However, the format and/or structure of the
ItemID is not stricly defined in this document, so long as uniqueness
is guaranteed.
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Publish request from VPN Forwarder to End-System Route Server:
<iq type='set'
from='forwarder@domain.org'
to='route-server@ietf.org'
id='request1'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<publish node='vpn-customer-name'>
<item id='192.0.2.1:1:203.0.113.42/32'>
<entry xmlns='urn:ietf:params:xml:ns:bgp:l3vpn:unicast'>
<nlri>
<af>1</af>
<address>203.0.113.42</address>
</nlri>
<next-hops>
<next-hop>
<af>1</af>
<address>192.0.2.1</address>
<label>10000</label>
<tunnel-encapsulation-list>
<tunnel-encapsulation>gre</tunnel-encapsulation>
<tunnel-encapsulation>udp</tunnel-encapsulation>
</tunnel-encapsulation-list>
</next-hop>
</next-hops>
<sequence-number>1</sequence-number>
</entry>
</item>
</publish>
</pubsub>
</iq>
In this example, the VPN Forwarder JID is "forwarder@domain.org".
The VPN Identifier "vpn-identifier" is used as the value of the node
attribute of the subscribe element. The IP address of the Virtual
Interface is 203.0.113.42/32. The IP address of the VPN Forwarder is
192.0.2.1 and it supports receiving MPLS packets via both GRE and UDP
tunneling. Label 10000 has been assigned to this particular Virtual
Interface.
The End-System Route Server will convert the information received in
a 'publish' request into the corresponding BGP route information such
that:
o It associates the specific request with a local VRF which it
resolves by using the Pub-Sub 'node' attribute.
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o It creates a BGP VPN route with a 'Route Distinguisher' (RD) which
contains a unique 32bit value per end-system plus a 16bit
instance-id, the specified IP prefix and 'label' received from the
VPN Forwarder as the Network Layer Reachability Information
(NLRI). The instance-id is either the value specified by the XMPP
client in the subscribe stanza for the specific pubsub node or a
locally generated value when that parameter is omitted.
o The BGP next-hop address is set to the address of the VPN
Forwarder.
o A BGP Tunnel Encapsulation Attribute [RFC5512] is generated for
each 'tunnel-encapsulation' element specified in the XMPP message.
o The route is optionally associated with a MAC Mobility extended
community [RFC7432] containing a sequence number for the route
advertisement.
Conversely, when an interface operational status is determined to be
down or an IP address is unconfigured the VPN forwarder generates an
XMPP retract message to withdraw the route advertisement.
Retract request from VPN Forwarder to End-System Route Server:
<iq type='set'
from='forwarder@domain.org'
to='route-server@ietf.org'
id='retract1'>
<pubsub xmlns='http://jabber.org/protocol/pubsub'>
<retract node='vpn-customer-name'>
<item id='192.0.2.1:1:203.0.113.42/32'/>
</retract>
</pubsub>
</iq>
The retract stanza uses the ItemId to identify the item being
retracted. The example retract stanza above uses the L3VPN NLRI
string representation ItemId format used in the publish example.
Consistent with XMPP Pub-Sub [pubsub], event notifications will be
generated whenever a VPN route is added, modified or deleted. This
is true for VPN routes learned via XMPP clients as well as routes
learned via BGP. For VPN routes that are learned via BGP (rather
than XMPP clients) the Route Server SHOULD create XMPP Pub-Sub
Publish stanzas or otherwise take steps to publish a persistent item
under the NodeID associated with the VPN Identifier of the
appropriate VRF(s). Thus the Pub-Sub node will contain items for
every route for the associated VPN. Upon successfully publishing a
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Pub-Sub item the XMPP server SHALL generate event notification
messages and send them to all VPN Forwarders that are actively
subscribed to that node. These event notification messages SHOULD be
sent as soon as possible (without delay) in order to facilitate
convergence and consistent reachability.
Example update notification message from Route Server to VPN
Forwarder:
<message to='forwarder@domain.org' from='route-server@ietf.org'>
<event xmlns='http://jabber.org/protocol/pubsub#event'>
<items node='vpn-customer-name'>
<item id='192.0.2.1:1:203.0.113.42/32'>
<entry xmlns='urn:ietf:params:xml:ns:bgp:l3vpn:unicast'>
<nlri>
<af>1</af>
<address>203.0.113.42/32</address>
</nlri>
<next-hops>
<next-hop>
<af>1</af>
<address>192.0.2.1</address>
<label>10000</label>
<tunnel-encapsulation-list>
<tunnel-encapsulation>gre</tunnel-encapsulation>
<tunnel-encapsulation>udp</tunnel-encapsulation>
</tunnel-encapsulation-list>
</next-hop>
</next-hops>
<sequence-number>1</sequence-number>
</entry>
</item>
<item >
...
</item>
</items>
</event>
</message>
Notification messages SHOULD be generated whenever a VPN route is
added, modified or deleted. These notification messages SHOULD
contain only items that have been added, modified or deleted since
any previous information that was sent to the VPN Forwarder.
Notification messages can be segmented at the convenience of the
Route Server.
Note that the Update from the Route Server to the VPN Forwarder does
not contain the JID of the destination end-system. The "from"
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attribute in the 'message' element contains the Route Server JID.
The XMPP messages are point-to-point in nature, between a Forwarder
and Route Server, even in the case when one XMPP publish request from
a Forwarder may cause the Route Server to generate one or more event
notifications.
When multiple possible routes exist for a given VPN IP address within
a VRF it is the responsibility of the Route Server to select the best
path to advertise to the VPN Forwarders. The routing entries
published by the Route Server to VPN Forwarders MAY include multiple
next-hops for the same forwarding entry. While BGP L3VPN NLRI
encodes a single next-hop, multiple NLRI with different RDs may
result in a single forwarding entry in a VRF with multiple next-hops.
This functionality is known as "vrf multipath" in standard BGP L3VPN
implementations. This "vrf multipath" behavior can be applied to
both BGP and XMPP learned routing information. The criteria used for
multipath selection is outside the scope of this document but SHOULD
be consistent between the Route Servers within an administrative
domain.
A VPN Forwarder uses locally originated information to generate MPLS
label forwarding state, and this used to forward downstream traffic
(i.e., traffic received from the network). Upstream traffic (i.e.,
received from a virtual interface) is forwarded according to the
routing information received from one or more Route Servers that the
VPN forwarder has an XMPP session with. In the case where multiple
Router Servers are providing routing information for a specific NLRI
the VPN Forwarder SHOULD select the following algorithm:
o Prefer the highest local-preference value
o Prefer the highest sequence-number
o Tie-break on the Route Server IP address
When routes are withdrawn, the End-System Route Server generates an
item "retract" request.
Route advertisements can have an optional sequence-number which help
the route server determine the most recent route advertisement. The
sequence number is determined by a mechanism outside the scope of
this document. One option is to use time synchronization between
compute nodes in order to have a globally coordinated timestamp.
This timestamp can be used to identify the time of interface creation
on the compute node.
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Routes can also be associated with a "local-preference" attribute.
This attribute maps to the BGP attribute of the same name for the
purposes of route selection.
7. End-System Route Server behavior
End-System Route Servers SHALL support the BGP address families: VPN-
IPv4 (1, 128), VPN-IPv6 (2, 128) and RT-Constraint (1, 132)
[RFC4684].
When an End-System Route Server receives a request to create or
modify a VPN route it SHALL generate a BGP VPN route advertisement
with the corresponding information.
It is assumed that the End-System Route Servers have information
regarding the mapping between the tuple ('end-system', 'vpn-name')
and the BGP Route Targets used to import and export information from
associated VRFs. This mapping is known via an out-of-band mechanism
not specified in this document.
Whenever the End-System Route Server receives an XMPP subscription
request, it SHALL consult its RT-Constraint Routing Information Base
(RIB). If the Route Server does not have a locally originated RT-
Constraint route that corresponds to the vpn-name present in the
request, it SHALL create one and generate the corresponding BGP route
advertisement. This route advertisement should only be withdrawn
when there are no more downstream XMPP clients subscribed to the VPN.
End-System Route Servers SHOULD automatically assign a BGP route
distinguisher per VPN routing table.
8. Operational Model
In the simplest case, a VPN is a collection of systems that are
allowed to exchange traffic with each other, and only with each
other. Since all the forwarding tables in this VPN have the same
routing entries they are often referred to as symmetrical VPNs.
In order to better illustrate the operation of the protocol, we
consider a simple example in which host H1 and host H2 both contain a
virtual interface that is a member of the same VPN.
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.------.
+----+ +-----+ / \ +-----+ +----+
| H1 | <===> | RS1 | <===> ( BGP mesh ) <===> | RS2 | <===> | H2 |
+----+ +-----+ \ / +-----+ +----+
`------'
Example Network with Two Hosts and Two Route Servers
Figure 2
Each of these hosts has a collocated VPN forwarder that has an XMPP
session with an End-System Route Server, RS1 and RS2 our example, and
these Route Servers are part of the same BGP mesh.
When a virtual interface is created on host H1, the local XMPP client
generates an XMPP subscription stanza to its respective Route Server.
This stanza contains a VPN identifier that has been assigned by the
provisioning system. The Route Server maps that identifier to a BGP
IP VPN configuration which contains the list of import and export
route targets to be used for that particular VRF.
Once the interface is operational, host H1 will publish any IP
addresses that are configured on the respective virtual interface.
This will in turn cause the End-System Route Server to advertise
these (directly or indirectly) to any other BGP speaker on the
network which is connected to an attachment point of that VPN.
The following table represents the contents of the VRF routing table
on RS1 after the IPv4 address 203.0.113.42 has been added to the
virtual interface on H1.
+-----------------+---------------+-------+-----------+
| VPN IP address | NEXT-HOP | label | Known via |
+-----------------+---------------+-------+-----------+
| 203.0.113.42/32 | 192.0.2.1 | 16 | XMPP |
| | | | |
| 203.0.113.48/32 | 198.51.100.10 | 20 | BGP |
+-----------------+---------------+-------+-----------+
It assumes that there is an attachment point for this VPN with the
IPv4 address of 203.0.113.48 which is advertising a route to the IP
address of an application running on H2 (203.0.113.48/32). Host H1
has an infrastructure IP address of 192.0.2.1 configured on its
physical interface while host H2 has IP address 198.51.100.10.
The contents of the VRF routing table in the End-System Route Servers
are advertised via XMPP Update notifications sent to H1, and a route
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update for the IP address of H1 will be sent into the BGP mesh on to
Route Server RS2 and from there, via XMPP to H2.
This information is used by the host to populate the forwarding table
associated with that VPN. The following shows the VRF table on host
H1
+-----------------+---------------+-------+
| VPN IP address | Host address | label |
+-----------------+---------------+-------+
| 203.0.113.42/32 | localhost | 16 |
| | | |
| 203.0.113.48/32 | 198.51.100.10 | 20 |
+-----------------+---------------+-------+
When an application that uses the virtual interface on host H1
generates packets with a destination IP address of 203.0.113.48 these
are routed by the VPN Forwarder implemented in the Host OS. The
packets are encapsulated with a header that contains a label assigned
by host H2, as shown in the figure, below.
+--------+ +--------+
app -- veth0 --| H1 |=== [network] ===| H2 |-- veth0 -- app
+--------+ +--------+
IP pkt ===> encap (GRE + label) ===> [IP net] ===> decap ===> IP pkt
[192.51.100.10, 20] map 20 to veth0
Packet Flow from Application in H1 to Application in H2
Figure 3
In the case that the virtual interface on the host is associated with
a guest OS, this guest OS has had its address resolution queries
answered with the Virtual Router MAC address, or the MAC address of
the destination MAY be supplied if it is in the same IP subnet
(broadcast domain). When the Virtual Router MAC address is supplied,
this is the address the guest OS uses as the destination MAC address
in packets it originates that are outside its IP subnet. The VPN
forwarder will replace the its MAC address with the MAC address of
the next hop in the tenant virtual network (another End System or
default gateway, for instance) before encapsulating the packet.
packet.
End-System Route Servers are software applications that implement
both the BGP IP VPN PE control plane as well as XMPP server
functionality. These applications are not in the forwarding plane
and MAY not be co-located with a network device.
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Network devices MAY have direct BGP sessions to the End-System Route
Servers. For instance, a router or security appliance that supports
BGP/MPLS IP VPNs over GRE may use its existing functionality to
inter-operate directly with a collection of Virtual Machines or other
network appliances that support this specification.
End-System Route Servers implement the VRF import policy and export
policy functionality that is associated with PE routers in standard
BGP IP/VPN deployments. VPN Forwarders receive forwarding
information after policy and route selection is applied. These are
unqualified routes in a specific VRF rather than VPN routing
information qualified by a Route Distinguisher and with a set of
Route Targets.
A symmetrical VPN uses a vrf import and vrf export polices that
contain a single route target, where the route target used for both
import and export is the same.
Different VPN topologies can be created by manipulating the vrf
import and export configuration including "hub-and-spoke" topologies
or overlapping VPNs.
An example of a hub-and-spoke VPN configuration is one where all the
traffic from the VPN clients must be redirected though a middle-box
for inspection. Assume that the virtual interfaces of a particular
user are configured to be in the VPN "tenant1". At an initial stage
this "tenant1" VPN is symmetrical and uses a single Route Target in
both its import and export policies. The middle-box functionality
can be incrementally deployed by defining a new VPN, "tenant1-hub",
and an associated Route Target. The End-System Route Server
configuration is changed such that VPN "tenant1" only imports routes
with the Route Target associated with the hub. The "hub" VPN is
assumed to advertise a prefix that covers all the VPN clients IP
addresses. The "hub" VPN imports the VPN routes in order for it to
be able to generate the XMPP updates to the "hub" end-system. This
information is required for the return traffic from the hub to the
spokes (the VPN clients). In such a scenario, a single physical
interface can connect the middle-box to the clients in a given VPN
which appear logically as downstream from it. Such a middle-box
would often require connectivity to multiple VPNs, such as, for
instance, an "outside" VPN which provides external connectivity to
one or more "inside" VPNs.
The functionality defined in this document in which the BGP IP VPN PE
functionality is split into its control (End-System Route Servers)
and forwarding (VPN Forwarder) components is fully interoperable with
existing BGP IP VPN PEs.
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This makes it possible to reuse existing systems. For example, at
the edge of a data center facility it may be desirable to use an
existing router or appliance that aggregates IP VPN routing
information and/or provides IP based services such as stateful packet
inspection.
Such a system can be configured, based on existing functionality, to
suppress more specific routes than a specified aggregate while
advertising the aggregate with a BGP NEXT_HOP containing the PE's IP
address and a locally assigned label corresponding to a VRF where the
more specific routes are present.
9. IANA Considerations
IANA has allocated the value 13 corresponding to "MPLS in UDP
Encapsulation" from the "BGP Tunnel Encapsulation Attribute Tunnel
Types" registry, using this document as reference. We request that
this allocation be made permanent.
This document defines a URN namespace used to encode L3VPN Unicast
routing information compliant with the registration procedure define
in [RFC3688].
URI: urn:ietf:params:xml:ns:bgp:l3vpn:unicast
Description: This is the XML namespace name for L3VPN Unicast
routing information.
Registrant Contact: IETF BESS Working Group <bess@ietf.org>
10. Security Considerations
As with BGP/MPLS L3VPN, we assume that the tenant networks have no
direct reachability to the infrastructure network. The threat models
to consider are:
o The possibility that an attacker on a tenant network may inject
traffic to a different network (for instance belonging to a
different tenant).
o Denial of service attacks from within a tenant network.
o Attacks from a tenant network to the infrastructure via
unauthorized or malicious control traffic.
o Attacks from within the infrastructure network.
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Traffic in BGP/MPLS L3VPNs is forwarded based on the contents of VRF
tables, calculated according to configured routing policy (route-
target import/export policies). It is assumed that the configuration
management system responsible for provisioning these policies only
accepts requests that are correctly authenticated, and follow a pre-
defined access policy. It is also assumed that an attacker doesn't
have the ability to inject packets in the infrastructure that mimic
the encapsulated used between PE devices. This specification
recommends that operators ensure that MPLS over GRE and MPLS over UDP
traffic is not allowed to enter the infrastructure network. VPN
forwarders MAY also choose to perform a reverse path forwarding
lookup (i.e., lookup the source IP address of the payload packet) and
discard traffic that doesn't match the expected next-hop(s) for the
reverse route.
As with BGP/MPLS L3VPN, an attacker on a tenant network may inject
packets that consume a disproportional share of infrastructure
resources, either in terms of bandwidth or CE packet forwarding
capacity. VPN forwarders SHOULD provide the ability to rate limit
traffic from a specific virtual interface. When the VPN forwarder
uses other finite resources on a per traffic basis, such as internal
tables used to cache the result access control validation, it SHOULD
provide a mechanism to limit the usage of these resources on a per
virtual interface basis.
The control protocol exchanges between application instances (e.g.,
the virtual machine) behind a virtual interface and the VPN forwarder
are typically limited to ARP/ND exchanges and the proxying of
services such as DHCP and DNS. The ARP/ND information received from
the application instance SHOULD NOT be used to populate routing or
forwarding tables directly. The control of what MACs and IP
addresses are accepted by a virtual interface SHOULD reside in the
configuration management system that creates said virtual interface.
The XMPP session between end-systems and the Route Servers SHOULD use
TLS with mutual authentication. One possible strategy is to
distribute pre-signed certificates to end-systems which are presented
as proof of authorization to the Route Server. BGP sessions SHOULD
be authenticated. This document recommends that BGP speaking systems
filter traffic on port 179 such that only IP addresses which are
known to participate in the BGP signaling protocol are allowed.
11. XML schema
The following schema defines the XML elements that are used to
communicate unicast reachability information between the Route Server
and VPN Forwarder:
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<xsd:schema xmlns:xsd="http://www.w3.org/2001/XMLSchema"
targetNamespace=
"urn:ietf:params:xml:ns:bgp:l3vpn:unicast">
<xsd:simpleType name="TunnelEncapsulationType">
<xsd:restriction base="xsd:string">
<xsd:enumeration value="gre"/>
<!-- RFC 4023 -->
<xsd:enumeration value="udp"/>
<!-- RFC 7510 -->
<xsd:enumeration value="vxlan"/>
<!-- RFC 7348 -->
</xsd:restriction>
</xsd:simpleType>
<xsd:complexType name="TunnelEncapsulationListType">
<xsd:sequence>
<xsd:element name="tunnel-encapsulation"
type="TunnelEncapsulationType"
maxOccurs="unbounded"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="NextHopType">
<xsd:sequence>
<xsd:element name="af" type="xsd:integer"/>
<xsd:element name="address" type="xsd:string"/>
<xsd:element name="label" type="xsd:integer"/>
<xsd:element name="tunnel-encapsulation-list"
type="TunnelEncapsulationListType"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="NextHopListType">
<xsd:sequence>
<xsd:element name="next-hop" type="NextHopType"
maxOccurs="unbounded"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="IPAddressType">
<xsd:sequence>
<xsd:element name="af" type="xsd:integer"/>
<xsd:element name="safi" type="xsd:integer"/>
<xsd:element name="address" type="xsd:string"/>
</xsd:sequence>
</xsd:complexType>
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<xsd:complexType name="EntryType">
<xsd:all>
<xsd:element name="nlri" type="IPAddressType"/>
<xsd:element name="next-hops" type="NextHopListType"/>
<xsd:element name="sequence-number" type="xsd:integer"/>
<xsd:element name="local-preference" type="xsd:integer"/>
</xsd:all>
</xsd:complexType>
<xsd:complexType name="ItemType">
<xsd:sequence>
<xsd:element name="entry" type="EntryType"/>
</xsd:sequence>
</xsd:complexType>
<xsd:complexType name="ItemsType">
<xsd:sequence>
<xsd:element name="item" type="ItemType"
maxOccurs="unbounded"/>
</xsd:sequence>
</xsd:complexType>
<xsd:element name="items" type="ItemsType"/>
</xsd:schema>
12. Acknowledgements
Pedro Marques contributed much of the original content of this
document.
Yakov Rekhter has contributed to this document by providing detailed
feedback and suggestions.
The authors would also like to thank Thomas Morin for his comments.
Amit Shukla and Ping Pan contributed to earlier versions of this
document.
Benson Schliesser provided a detailed review of the document and
helped clarify several sections.
13. References
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13.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<http://www.rfc-editor.org/info/rfc2119>.
[RFC3688] Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
DOI 10.17487/RFC3688, January 2004,
<http://www.rfc-editor.org/info/rfc3688>.
[RFC4023] Worster, T., Rekhter, Y., and E. Rosen, Ed.,
"Encapsulating MPLS in IP or Generic Routing Encapsulation
(GRE)", RFC 4023, DOI 10.17487/RFC4023, March 2005,
<http://www.rfc-editor.org/info/rfc4023>.
[RFC4364] Rosen, E. and Y. Rekhter, "BGP/MPLS IP Virtual Private
Networks (VPNs)", RFC 4364, DOI 10.17487/RFC4364, February
2006, <http://www.rfc-editor.org/info/rfc4364>.
[RFC4456] Bates, T., Chen, E., and R. Chandra, "BGP Route
Reflection: An Alternative to Full Mesh Internal BGP
(IBGP)", RFC 4456, DOI 10.17487/RFC4456, April 2006,
<http://www.rfc-editor.org/info/rfc4456>.
[RFC4684] Marques, P., Bonica, R., Fang, L., Martini, L., Raszuk,
R., Patel, K., and J. Guichard, "Constrained Route
Distribution for Border Gateway Protocol/MultiProtocol
Label Switching (BGP/MPLS) Internet Protocol (IP) Virtual
Private Networks (VPNs)", RFC 4684, DOI 10.17487/RFC4684,
November 2006, <http://www.rfc-editor.org/info/rfc4684>.
[RFC5512] Mohapatra, P. and E. Rosen, "The BGP Encapsulation
Subsequent Address Family Identifier (SAFI) and the BGP
Tunnel Encapsulation Attribute", RFC 5512,
DOI 10.17487/RFC5512, April 2009,
<http://www.rfc-editor.org/info/rfc5512>.
[RFC5798] Nadas, S., Ed., "Virtual Router Redundancy Protocol (VRRP)
Version 3 for IPv4 and IPv6", RFC 5798,
DOI 10.17487/RFC5798, March 2010,
<http://www.rfc-editor.org/info/rfc5798>.
[RFC6120] Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Core", RFC 6120, DOI 10.17487/RFC6120,
March 2011, <http://www.rfc-editor.org/info/rfc6120>.
Mackie, et al. Expires June 18, 2017 [Page 29]
Internet-Draft BGP-Signaled End-System IP/VPNs December 2016
[RFC7348] Mahalingam, M., Dutt, D., Duda, K., Agarwal, P., Kreeger,
L., Sridhar, T., Bursell, M., and C. Wright, "Virtual
eXtensible Local Area Network (VXLAN): A Framework for
Overlaying Virtualized Layer 2 Networks over Layer 3
Networks", RFC 7348, DOI 10.17487/RFC7348, August 2014,
<http://www.rfc-editor.org/info/rfc7348>.
[RFC7432] Sajassi, A., Ed., Aggarwal, R., Bitar, N., Isaac, A.,
Uttaro, J., Drake, J., and W. Henderickx, "BGP MPLS-Based
Ethernet VPN", RFC 7432, DOI 10.17487/RFC7432, February
2015, <http://www.rfc-editor.org/info/rfc7432>.
[RFC7510] Xu, X., Sheth, N., Yong, L., Callon, R., and D. Black,
"Encapsulating MPLS in UDP", RFC 7510,
DOI 10.17487/RFC7510, April 2015,
<http://www.rfc-editor.org/info/rfc7510>.
[RFC7622] Saint-Andre, P., "Extensible Messaging and Presence
Protocol (XMPP): Address Format", RFC 7622,
DOI 10.17487/RFC7622, September 2015,
<http://www.rfc-editor.org/info/rfc7622>.
[xep-0004]
Eatmon, R., Hildebrand, J., Miller, J., Muldowney, T., and
P. Saint-Andre, "Data Forms", XEP 0004, August 2007.
[pubsub] Millard, P., Saint-Andre, P., and R. Meijer, "Publish-
Subscribe", XEP 0060, July 2010.
13.2. Informational References
[RFC1027] Carl-Mitchell, S. and J. Quarterman, "Using ARP to
implement transparent subnet gateways", RFC 1027,
DOI 10.17487/RFC1027, October 1987,
<http://www.rfc-editor.org/info/rfc1027>.
[RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J.,
and D. McPherson, "Dissemination of Flow Specification
Rules", RFC 5575, DOI 10.17487/RFC5575, August 2009,
<http://www.rfc-editor.org/info/rfc5575>.
[RFC5880] Katz, D. and D. Ward, "Bidirectional Forwarding Detection
(BFD)", RFC 5880, DOI 10.17487/RFC5880, June 2010,
<http://www.rfc-editor.org/info/rfc5880>.
Mackie, et al. Expires June 18, 2017 [Page 30]
Internet-Draft BGP-Signaled End-System IP/VPNs December 2016
[RFC7365] Lasserre, M., Balus, F., Morin, T., Bitar, N., and Y.
Rekhter, "Framework for Data Center (DC) Network
Virtualization", RFC 7365, DOI 10.17487/RFC7365, October
2014, <http://www.rfc-editor.org/info/rfc7365>.
[IEEE.802-1Q]
Institute of Electrical and Electronics Engineers, "Local
and Metropolitan Area Networks: Virtual Bridged Local Area
Networks", IEEE Std 802.1Q-2005, May 2006.
Authors' Addresses
Stuart Mackie
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
Email: wsmackie@juniper.net
Luyuan Fang
eBay
2025 Hamilton Avenue
San Jose, CA 95125
Email: lufang@ebay.com
Nischal Sheth
Juniper Networks
1133 Innovation Way
Sunnyvale, CA 94089
Email: nsheth@juniper.net
Maria Napierala
AT&T Labs
200 Laurel Avenue
Middletown, NJ 07748
Email: mnapierala@att.com
Nabil Bitar
Nokia
Email: nabil.bitar@nokia.com
Mackie, et al. Expires June 18, 2017 [Page 31]
